Bending brake machine

ABSTRACT

A bending machine includes a base frame and arms hingedly coupled to the base frame. The arms include a jaw for clamping a workpiece to be bent. The bending machine also includes a shaft including eccentric shaft portions. The eccentric shaft portions couple the arms to the base frames and have a first eccentric axis and a second eccentric axis. The first and second eccentric longitudinal axes are spaced apart such that the arms rotate and translate as the eccentric shaft portions are rotated about the first eccentric axis. The shaft also includes at least one connecting shaft portion that interconnects the eccentric shaft portions.

FIELD OF THE INVENTION

[0001] The present invention relates to bending brake machines, and more particularly to sheet metal bending brake machines.

BACKGROUND OF THE INVENTION

[0002] Bending brake machines are widely known in the art. One such bending brake machine is the Auto Max bending brake manufactured and sold by Roper Whitney of Rockford, Inc. of Rockford, Ill. Bending brake machines, such as the Auto Max, are generally hydraulically driven, automated, CNC controlled, folding systems adapted for sheet metal fabrication. Generally, in these types of machines, a work piece, i.e., a piece of sheet metal, is supported on a work table between an upper beam or clamp jaw and a lower beam or clamp jaw. A clamping pressure is provided between the clamping jaws to hold the sheet metal during the bending process. The clamping pressure is typically created by one or more hydraulically operated cylinders. In the past, such hydraulic cylinders have utilized cast iron rings to separate the pressure chambers of the cylinders.

[0003] As can be appreciated by those of ordinarily skill in the art, it is desirable to use a minimum amount of loading pressure to sufficiently clamp a work piece so as not to distort the work piece during the bending process. A problem with using cast iron rings in the loading cylinders is that as the cast iron rings begin to wear, hydraulic fluid can leak around the rings, thereby adversely affecting the holding or clamping power of the cylinders. To offset such a situation, those in the art have been known to increase the initial clamping pressure between the clamping jaws so as to ensure that an appropriate amount of clamping pressure is still provided to the jaws when the bending process is nearly completed. A problem with this known method is that it is possible to distort the work piece because of the excessive initial clamping pressure, thereby resulting in a potentially defective finished product. Another problem with this known method is that the less than precise clamping pressures affect the operator's ability to form the desired end product.

[0004] Bending brake machines such as those described above generally include a plurality of c-shaped arms for supporting the upper beam. The c-shaped arms are supported by a shaft, which generally extends along the backside length of the machine. The upper beam and c-shaped arms are pivotable about a generally horizontal axis extending through the shaft. However, in order to accommodate materials of different thickness, the shaft includes eccentric portions.

[0005] For example, prior c-shaped arms typically included a bore extending completely therethrough for receiving a sleeve bearing, typically made of bronze or brass. The connection between the bore surface and the outer surface of the sleeve bearing is usually a press fit connection. The sleeve bearing is generally not adapted to rotate within the bore. The sleeve bearing is concentric with respect to an axis extending through the center of the bore. The inner diameter of the sleeve bearing is generally impregnated with an oil lubricant or the like to provide a slippery surface for reasons which will be apparent below. An eccentric sleeve is positioned within the sleeve bearing. The outer diameter of the eccentric sleeve is concentric with the sleeve bearing, but the inner diameter of the eccentric sleeve is eccentric with respect to the sleeve bearing. The shaft is positioned through the eccentric sleeves in such a manner that the shaft and eccentric sleeves will rotate as one. Thus, to accommodate materials having different thicknesses, the shaft and, therefore, the eccentric sleeves, are rotated with respect to the sleeve bearings. As the shaft and eccentric sleeves rotate within the sleeve bearings, the relative position of the c-shaped arms with respect to the machine frame will move.

[0006] In general, the shaft as described above is typically made of a single piece of material, which extends along substantially the entire backside length of the machine. However, such a shaft has been known to be cut in half and coupled together with an appropriate coupling device. In any event, machining the bores in the c-shaped arms to properly receive the sleeve bearings, pressing the sleeve bearings into the associated bores, inserting the eccentric sleeves into the associated sleeve bearings, and passing the shaft through the c-shaped arms, is a somewhat cumbersome and time consuming process. Thus, there is a need for a new eccentric assembly which, for example, is easier to use, reduces assembly time, and still includes features generally needed to handle materials having different thicknesses.

SUMMARY OF THE INVENTION

[0007] To address the foregoing problems and other problems, according to some embodiments of the present invention, a bending machine includes at least two base frames and at least two arms hingedly coupled to the base frames. The arms each include a jaw and are moveable between a first position, where the jaws are positioned away from the base frames, and a second position, where the jaws are positioned toward the base frames. The bending machine also includes a shaft including at least two eccentric shaft portions. The eccentric shaft portions couple the arms to the base frames and have a first eccentric longitudinal axis around which the eccentric shaft portions rotate. In addition, the eccentric shaft portions have a second eccentric longitudinal axis, which runs through the geometric center of the eccentric shaft portions. The first and second eccentric longitudinal axes are spaced apart such that the arms rotate and translate as the eccentric shaft portions are rotated about the first longitudinal axis. The shaft also includes at least one connecting shaft portion that interconnects the eccentric shaft portions.

[0008] According to other embodiments of the present invention, a bending brake machine for bending a workpiece is provided. The bending brake machine includes a base frame having a first working beam and a modular shaft that is rotatably supported by the base frame. The modular shaft includes shaft portions and at least one connecting portion. Each shaft portion has a concentric portion that defines a first axis, and an eccentric portion that defines a second axis that is spaced from the first axis. The connecting portion extends between and couples the shaft portions to each other. The bending break machine also includes a plurality of sub frame arms that are pivotally supported by the eccentric portions. The sub frame arms provide a second working beam that cooperates with the first working beam to clamp the workpiece. The sub frame arms move with respect to the base frame when the modular shaft is rotated about the first axis.

[0009] The present invention provides a method for making a bending brake machine for bending a workpiece. The method includes determining a maximum length and thickness of a workpiece to be bent by the bending brake machine. A base frame having a first working beam including a length corresponding to the determined maximum workpiece length is provided and a required quantity of, and spacing between, sub frame arms is calculated based upon the determined maximum workpiece length and thickness. A shaft portion including a concentric portion and an eccentric portion is formed for each sub frame arm, and each shaft portion is extended through a respective sub frame arm such that the eccentric portion of each shaft engages the sub frame arm. Connecting portions are formed having lengths corresponding to the spacing between the sub frame arms and the connecting portions are coupled between the shaft portions to form a single, modular shaft that is rotatably coupled to the base frame.

[0010] The present invention also provides a modular shaft for a bending brake machine that includes a base frame having a first jaw and at least two arms hingedly coupled to the base frame and providing a second jaw. The modular shaft includes at least two shaft portions that couple the arms to the base frame. Each shaft portion includes an eccentric portion that is receivable by a respective arm and that defines an eccentric axis. Each shaft portion also includes at least one concentric portion that extends from the respective arm, is rotatably coupleable to the base frame, and that defines a concentric axis. The eccentric axis and the concentric axis are spaced from each other. The modular shaft further includes at least one connecting portion that is coupled to and extends between the concentric portions. The connecting portion includes a central axis that is substantially aligned with the concentric axis. The entire modular shaft is rotatable about the concentric axis to adjust a relative position between the first jaw and the second jaw.

[0011] Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is an end view of a bending brake machine embodying the invention.

[0013]FIG. 2 is a top view of the bending brake machine of FIG. 1.

[0014]FIG. 3 is a front view, partially in section, of a portion of the bending brake machine of FIG. 1.

[0015]FIG. 4 is a top view of an eccentric shaft portion of the bending brake machine of FIG. 1.

[0016]FIG. 5 is a side view of the eccentric shaft portion of FIG. 4.

[0017]FIG. 6 is an end view of the eccentric shaft portion of FIG. 4.

[0018]FIG. 7 is an end view of a material adjustment portion of the bending brake machine of FIG. 1.

[0019]FIG. 8 is a section view taken along line 8-8 of FIG. 1.

[0020] Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.

DETAILED DESCRIPTION

[0021] A bending brake machine 10 embodying the invention is illustrated in the drawings. It should be understood that the present invention is capable of use in other bending brake machines and the bending brake machine 10 is shown and described as an example of one such machine.

[0022] Referring to FIGS. 1 and 2, the bending brake machine 10 includes a base frame 14 and a plurality of c-frame arms 18. It should be noted that the base frame could be made of individual base frames corresponding to the number of c-frames. The c-frame arms 18 are spaced apart and positioned along the backside length of the base frame 14. The base frame 14 supports a lower beam or jaw 19, and the c-frame arms 18 support an upper beam or jaw 20 as conventionally understood. A workpiece clamping pressure between the upper and lower beams 19, 20 is hydraulically controlled by hydraulic cylinders 21. A no-leak seal, preferably a lip-tight seal, is provided in each hydraulic cylinder 21 to substantially prevent any leaking around the seal. In this way, the desired clamping pressure is substantially held throughout the bending process.

[0023] Each c-frame arm 18 includes a bore 22 (see FIG. 3) extending therethrough. The c-frame arms 18 are coupled to the base frame 14 by a modularized shaft 30 according to the present invention. The shaft 30 comprises a plurality of eccentric shafts 34 and connecting tubes 38 extending therebetween. Reference to one eccentric shaft can be viewed as reference to the others. Likewise, reference to one tube can be viewed as reference to the others. Referring to FIGS. 3-6, the eccentric shaft 34 includes a first end portion 42, a middle portion 46 and a second end portion 50. The middle portion 46 includes an axis 51 (see FIG. 4) and fits in the bore 22 of an associated c-frame 18. The end portions 42, 50 include a common axis 52 and extend outwardly with respect to opposite sides of the associated c-frame 18. The end portions 42, 50 are coupled to the base frame 14 by respective pillow blocks or bearing housings 48. The outer diameter 54 of the middle portion 46 (and thus the axis 51 of the middle portion 46) is eccentric with a rotational axis of the bearing housings 48 while the outer diameters of the respective end portions 42, 50 (and thus the common axis 52 of the end portions 42, 50) are concentric with respect to the rotational axis of the bearing housings 48. As such, the middle portion axis 51 and the end portion common axis 52 are spaced from each other. As the shaft 30 rotates within the bearing housings 48, the eccentric middle portions 46 of the shaft sections 34 engage the bores 22 of the c-frame arms 18 and effectuates simultaneous translational and rotational movement of the c-frames 18 with respect to the frame 14.

[0024] Located on an end of each end portion 42, 50 is a protruding male tang member 58. Tool holding portions 62 may be provided in one or both ends of the tang members 58 for machining purposes. Tubes 38 may be of different shapes and configurations, but a thick walled tube works well according to the present invention. Each tube 38 has a longitudinal axis and functions to connect pairs of eccentric shafts 34 together, thereby forming a complete shaft 30. When assembled, the longitudinal axis of each tube 38 is collinear with the common axis 52 of the end portions 42, 50. Each end of each tube 38 includes a female receptacle portion or slot 66 for receiving an associated male tang member 58 of one of the eccentric shafts 34. In this way, the milled slots 66 can be slip fitted over the ends of the associated shafts to create a continuous shaft 30. A sleeve 70 (see FIG. 3) is positioned over each connection point between a shaft 34 and tube 38 to hold the shaft 34 and tube 38 in intimate contact. A snap-ring is snapped over the tube 38 near one end of the sleeve 70 to prevent lateral movement of the sleeve 70 in one direction. The associated bearing housing 48 supporting the shaft 34 prevents lateral movement of the sleeve 70 in the opposite direction.

[0025] Referring also to FIGS. 7 and 8, a material adjusting lever 74 is mounted to each end of the machine 10 (see FIG. 1). Material adjustment settings are preferably marked on the machine 10 for varying gauge sizes. The adjusting levers 74 are locked in place with associated locking pins 78. The adjusting levers 74 are adapted to connect to the male tang members 58 of the shaft sections 34 located at the ends of the machine 10. The adjusting levers 74 allow rapid adjustment of the relative positioning of the upper and lower beams 19, 20 for a broad range of material thicknesses. As the shaft 30 is rotated about the common axis 52 of the end portions 42, 50 due to movement of the adjusting levers 74, the c-frames 18 move with respect to the frame 14 because of the eccentric middle portions 46 of the shaft sections 34.

[0026] The shaft sections 34 can be zinc coated to increase operating life. Lubricating oils or greases can be used where desired to decrease wear on moving components.

[0027] Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art.

[0028] Various features of the invention are set forth in the following claims. 

What is claimed is:
 1. A bending machine comprising: at least two base frames; at least two arms hingedly coupled to the at least two base frames, the arms each including a jaw and moveable between a first position wherein the jaws are positioned away from the base frames and a second position wherein the jaws are positioned toward the base frames; and a shaft comprising at least two eccentric shaft, the eccentric shaft portions coupling the at least two arms to the at least two base frames and having a first eccentric longitudinal axis around which the eccentric shaft portions rotate and a second eccentric longitudinal axis, which runs through the geometric center of the eccentric shaft portions, the first and second eccentric longitudinal axes being spaced apart thereby causing the arms to both rotate and translate as the eccentric shaft portions rotate about the first longitudinal axis, the shaft further comprising at least one connecting shaft portion removably interconnecting the at least two eccentric shaft portions.
 2. The bending machine of claim 1, wherein the at least one connecting shaft portion has a first connecting longitudinal axis around which the connecting shaft portion rotates and a second connecting longitudinal axis, which runs through the geometric center of the connecting shaft, the two connecting longitudinal axes being collinear.
 3. The bending machine of claim 2, wherein the first eccentric longitudinal axis and the first connecting longitudinal axis are collinear.
 4. The bending machine of claim 1, wherein the connecting shaft portion is tubular.
 5. The bending machine of claim 4, wherein the eccentric shaft portion includes a tang protruding from an end of the eccentric shaft portion, the tang engaging a slot in the connecting shaft portion.
 6. The bending machine of claim 5, further comprising a sleeve receiving the eccentric shaft portion and the connecting shaft portion and surrounding the tang and the slot.
 7. A bending brake machine for bending a workpiece, the bending brake machine comprising: a base frame including a first working beam; a plurality of eccentric shafts, each eccentric shaft including a concentric portion having a first axis, and an eccentric portion having a second axis spaced from the first axis; a plurality of sub frame arms, each subframe arm pivotally supported by a respective one of the eccentric shafts and defining a second working beam that cooperates with the first working beam to clamp the workpiece; and at least one connecting shaft extending between adjacent sub frame arms and removably coupled to the eccentric shafts, wherein the sub frame arms are movable with respect to the base frame in response to rotation of the eccentric shafts and the at least one connecting shaft.
 8. The bending brake machine of claim 7, wherein the sub frame arms are pivotable about the second axis to clamp the workpiece, the eccentric shafts and the at least one connecting shaft being pivotally fixed as the workpiece is clamped.
 9. The bending brake machine of claim 7, wherein each eccentric shaft includes two concentric portions and the eccentric portion extends therebetween.
 10. The bending brake machine of claim 7, wherein the eccentric shafts each include a tang, and wherein each connecting shaft includes a slot formed on at least one end and engageable with a respective tang to couple the connecting shaft and the eccentric shaft.
 11. The bending brake machine of claim 10, wherein the tang is formed on the concentric portion.
 12. The bending brake machine of claim 7, wherein pivotal movement of the shafts about the first axis adjusts a relative positioning of the first working beam with respect to the second working beam, thereby facilitating the bending of workpieces having different thicknesses.
 13. A method for making a bending brake machine for bending a workpiece, the method comprising: determining a maximum length and thickness of a workpiece to be bent by the bending brake machine; providing a base frame having a first working beam including a length corresponding to the determined maximum workpiece length; calculating a required quantity of, and spacing between sub frame arms based upon the determined maximum workpiece length and thickness; forming a shaft portion including a concentric portion and an eccentric portion for each sub frame arm; extending each shaft portion through a respective sub frame arm, the eccentric portion of each shaft engaging the sub frame arm; forming connecting portions having lengths corresponding to the spacing between the sub frame arms; coupling the connecting portions between the shaft portions to form a single, modular shaft; and rotatably coupling the shaft to the base frame.
 14. The method of claim 13, further comprising providing a tang at an end of each shaft portion and engaging the tang with a slot formed in a respective connecting portion.
 15. The method of claim 13, wherein forming the shaft portion comprises machining the concentric portion and the eccentric portion from the same piece of material.
 16. The method of claim 13, wherein extending each shaft portion through a respective sub frame arm comprises inserting the eccentric portion of each shaft into a bushing that extends through the sub frame arm.
 17. The method of claim 13, wherein rotatably coupling the shaft to the base frame comprises extending the concentric portions of each shaft portion through a pillow block, and mounting the pillow block to the base frame.
 18. A modular shaft for a bending brake machine, the bending brake machine including a base frame having a first jaw and at least two arms hingedly coupled to the base frame and providing a second jaw, the modular shaft comprising: at least two substantially identical eccentric shafts, each eccentric shaft coupling one of the at least two arms to the base frame, each eccentric shaft including an eccentric portion receivable by a respective arm and defining an eccentric axis, and at least one concentric portion extending from the respective arm, rotatably coupleable to the base frame, and defining a concentric axis, the eccentric axis and the concentric axis being spaced from each other; and at least one connecting shaft coupled to and extending between the concentric portions, the connecting shaft including a central axis that is substantially aligned with the concentric axis, the modular shaft being rotatable about the concentric axis to adjust a relative position between the first jaw and the second jaw.
 19. The modular shaft of claim 18, wherein the at least one end of the connecting shaft includes a slot and the eccentric shaft includes a tang, the tang engageable with the slot to couple the connecting shaft and the eccentric shaft.
 20. The modular shaft of claim 19, further comprising a sleeve surrounding the tang and the slot to maintain alignment of the eccentric shaft and the connecting shaft.
 21. The modular shaft of claim 20, wherein the connecting shaft is substantially tubular.
 22. A system of bending brake machines, each machine having a plurality of arms hingedly coupled to at least one base frame, each arm having an end moveable between a first position away from the base frame and a second position toward the base frame, the arm securing a workpiece between the end and the base frame in its second position, each arm hingedly coupled to the at least one base frame by an eccentric shaft portion defining an eccentric axis spaced apart from a rotational axis around which the eccentric shaft portion rotates, the eccentric shaft portions being interchangeable and being removeably interconnected by connecting shaft portions which define a longitudinal axis which is colinear with the rotational axis.
 23. The system of bending brake machines of claim 22, wherein each connecting shaft portion includes two ends, each end being engageable with a tang protruding from an end of the eccentric shaft portion, each connecting shaft portion thereby removeably interconnecting two eccentric shaft portions.
 24. The system of bending brake machines of claim 23, further including a sleeve positioned around a joint defined at the location where the connecting shaft portion engages the tang. 